Comparative Efficacy of the First and the Second Middle Cranial Fossa Repair of Bilateral Superior Semicircular Canal Dehiscence

Objective: For patients with bilateral superior semicircular canal dehiscence (SSCD), prior research has demonstrated the potential benefits of undergoing the middle cranial fossa (MCF) surgery on both sides.[1] The present investigation explores the efficacy of the first repair as compared with the second repair on the contralateral side.

Methods: We conducted a retrospective review of MCF surgeries performed for bilateral SSCD at one institution from 2012 to 2022. Symptom questionnaires administered pre- and post-operatively assessed whether patients experienced each of the symptoms. Several variables were computed to evaluate surgical outcome. First, we assessed the resolution rate for each symptom (among patients who experienced that specific symptom preoperatively). Second, we calculated a % symptom resolution score, which was obtained by first subtracting the number of postoperative symptoms from the number of preoperative symptoms, then dividing that value by the number of preoperative symptoms. Outcome variables were evaluated in multivariable regression models. In each model, surgery order was applied as the primary independent variable of interest. Control measures including patient age, sex, prior ear surgery of the affected ear, and follow-up duration were applied as covariates.

Results: A total of 230 surgeries (175 first and 55 second) were included in this study. The mean age was 50 years, 68% of patients were female, and the average follow-up duration was 5 months. Compared with the first surgery, the second surgery was significantly less likely to resolve autophony (aOR 95% CI: 0.09–0.59, p = 0.002), hyperacusis (aOR 95% CI: 0.13–0.86, p = 0.02), internal amplification of sound (aOR 95% CI: 0.10–0.70, p = 0.007), oscillopsia (aOR 95% CI: 0.01–0.40, p = 0.003), and headache (aOR 95% CI: 0.05–0.70, p = 0.013). However, there was no significant difference in resolution rates between the first and the second surgery for disequilibrium (aOR 95% CI: 0.27–1.31, p = 0.20), vertigo (aOR 95% CI: 0.45–4.25, p = 0.58), dizziness (aOR 95% CI: 0.22–1.13, p = 0.10), aural fullness (aOR 95% CI: 0.21–1.41, p = 0.21), tinnitus (aOR 95% CI: 0.27–1.51, p = 0.31), and hearing loss (aOR 95% CI: 0.23–1.45, p = 0.24). Finally, % symptom resolution score for the second surgery was, on average, 20% lower compared with the first surgery (B: −20.03, 95% CI= [−35.73, −4.33], p = 0.013).

Conclusions: Our findings suggest that autophony, hyperacusis, internal amplification of sound, oscillopsia, and headache are less likely to resolve following the second surgery on the contralateral ear if not resolved by the first surgery. However, if disequilibrium, vertigo, dizziness, aural fullness, tinnitus, and hearing loss are not resolved following the first surgery, there remains substantial optimism that they can be resolved by the second surgery. Additionally, the overall proportion of preoperative symptoms resolved by the second surgery was significantly lower than that of the first surgery. These findings may help predict patient outcomes and determine the appropriateness of the second surgery.

Publication History

Article published online:
01 February 2023

• Reference

• 1 Mozaffari K, Willis SL, Unterberger A, et al. Superior semicircular canal dehiscence outcomes in a consecutive series of 229 surgical repairs with middle cranial fossa craniotomy. World Neurosurg 2021;156:e229–e234